On the physical meaning of the zonal components of the geopotential

The main target of the present study is to obtain a generalized form of the MacCullagh equation for even orders n ≥ 2 by including the higher order zonal coefficients Jn connected with the higher (n ≥ 2) degree moments of inertia Cn and An. The higher the degree n, the higher is the weight of the near-surface (i.e. shallow) mass density distribution in Jn. The second part of this contribution deals with the temporal variations of Jn, dJn/dt for n ≥ 2.